1. Field of the Invention
This invention relates generally to heat exchange of an electrical article and more particularly to cooling an integrated circuit chip.
2. Description of the Prior Art
The temperature of integrated circuit chips must be kept below specified limits to ensure proper function, reliability and useful life. The trend in integrated circuit technology is toward large scale integration which results in increased functions per chip. Also, system designers are mounting chips closer together to minimize propagation delays in the circuit interconnections. As a result of the foregoing, heat is not only increased for each chip but is also concentrated due to the closely mounted chips. Cooling of these chips is a problem.
A limitation of chip cooling is that compact areas are often too confining to provide adequate cooling. The prior art discloses that liquid cooling promises to be more compact than forced air convection. However, limitations to liquid cooling include increased cost due to complexity of cooling circuits, i.e. pumping and guiding liquid to and from the vicinity of the chips and cooling the fluid so that it can be recirculated in a closed loop system. Also, there is an inherent aversion to using a liquid within an electrical system due to the obvious problems created if leakage of the liquid should occur.
A heat sink having narrow air channels formed between adjacent fins has been mounted on one side of a board or substrate adjacent a respective chip which is mounted on an opposite side of the board. Heat from the chip is conducted through the substrate to the sink. Air moved through the channels and across the fins carries heat from the sink by convection. Heat conducted through substrate encounters the thermal resistance of the board.
The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations as set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.